drm/i915: only report hpd connector status change when it actually changed

This reduces dmesg noise when there's a glitch on the hpd line, or there
are more than one connectors on the same hpd line and only one of them
changes.

While at it, switch to use the friendly status names instead of numbers.

Signed-off-by: Jani Nikula <jani.nikula@intel.com>
Signed-off-by: Daniel Vetter <daniel.vetter@ffwll.ch>
diff --git a/drivers/gpu/drm/i915/i915_irq.c b/drivers/gpu/drm/i915/i915_irq.c
index 5350ef5..a610f5ab 100644
--- a/drivers/gpu/drm/i915/i915_irq.c
+++ b/drivers/gpu/drm/i915/i915_irq.c
@@ -665,7 +665,8 @@
 						     crtc);
 }
 
-static int intel_hpd_irq_event(struct drm_device *dev, struct drm_connector *connector)
+static bool intel_hpd_irq_event(struct drm_device *dev,
+				struct drm_connector *connector)
 {
 	enum drm_connector_status old_status;
 
@@ -673,11 +674,16 @@
 	old_status = connector->status;
 
 	connector->status = connector->funcs->detect(connector, false);
-	DRM_DEBUG_KMS("[CONNECTOR:%d:%s] status updated from %d to %d\n",
+	if (old_status == connector->status)
+		return false;
+
+	DRM_DEBUG_KMS("[CONNECTOR:%d:%s] status updated from %s to %s\n",
 		      connector->base.id,
 		      drm_get_connector_name(connector),
-		      old_status, connector->status);
-	return (old_status != connector->status);
+		      drm_get_connector_status_name(old_status),
+		      drm_get_connector_status_name(connector->status));
+
+	return true;
 }
 
 /*